<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
    <script crossorigin src="https://unpkg.com/react@17/umd/react.development.js"></script>
    <script crossorigin src="https://unpkg.com/react-dom@17/umd/react-dom.development.js"></script>
    <script src="https://unpkg.com/babel-standalone@6/babel.min.js"></script>

</head>
<body>
    <div id="app"></div>
<!--    ES5 方法创建-->
    <script>
        // 创建
        let hello = React.createElement('h1',{},'hello world') // 节点 节点属性 标签内容
        //展示
        ReactDOM.render(hello,document.getElementById('app'))
    </script>
</body>
</html>